Southwest Airlines SEA to STL on-time performance
Southwest Airlines nonstop flights from Seattle to St. Louis · Aug 2025 – Jul 2026
On-time arrivals
73%
arrived < 15 min late
Cancelled
1.0%
1 flights
Avg arrival delay
14 min
43 min when late
Rank on route
#2 of 2
route average 83% on time
Key facts
- Southwest Airlines flights on SEA to STL arrived on time 73% of the time in Aug 2025 – Jul 2026.
- 1% were cancelled, and 4% arrived an hour or more late.
- That ranks #2 of 2 airlines on this route, which averaged 83% on time overall.
- The largest source of delay minutes was late-arriving aircraft (61%).
On-time trend by month
Why this airline's flights were late
- Late-arriving aircraft61%
- Airline (crew, maintenance, cleaning, fueling)24%
- Air traffic control & airport congestion13%
- Security3%
- Extreme weather0%
Other airlines on SEA to STL
- Alaska Airlines84% on time · 8 min avg delay
Full SEA to STL comparison →
Southwest Airlines on-time record across all routes →
103 Southwest Airlines flights tracked on this route; 1 cancelled, 0 diverted.
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. How we calculate this.